Modular cutter beds have been known for some time. Generally speaking, they are formed by connecting a series of essentially identical cutter modules in end-to-end relationship along a support beam in such a manner that the length of the cutter bed is determined by the number of modules in the series. In some constructions, the modules may simply be secured to each other without being secured to a common support beam such that the resulting assembly is self-supporting. In either case, internal drive mechanisms such as operably interconnected spur gears or shafts and bevel gears form a drive train along the bed and provide driving power to all rotary cutters of the bed.
Due to the fact that the cutter bed is comprised of a series of interconnected modules, lines of weakness are inherently presented to some extent at the interfaces or seams between abutting ends of the adjacent modules. Thus, the structural integrity of the bed can be compromised to a certain extent, and reliability issues are presented with respect to the interconnected drive mechanisms between the modules. Each module also has its own rock guard with side edges that end at the seam between adjacent modules. Because these guards do not overlap adjacent modules and interconnect with them, the guards provide no assistance in structurally supporting adjacent modules.
In one conventional arrangement the cutter bed has a scalloped front extremity in which a series of rearwardly projecting notches are interspersed between a series of forwardly projecting arches. This pattern is presented by the rounded noses of the rock guards whose opposite side edges are located at the recessed notches and present fore-and-aft joints at those locations. The cutters of adjacent modules counter-rotate and sweep rearwardly in overlapping paths of travel directly above the notches and joints. Consequently, the cutters tend to drive residue and dirt directly into the joints and can cause it to become tightly wedged in those spaces. A cradle that supports the modules may have grooves worn into it as stubble drags through the joints and into engagement with the cradle.
In the present invention each rock guard is designed to span the seam between a pair of adjacent modules so that it overlaps the two modules and is secured thereto in a bridging relationship to provide improved structural rigidity. Moreover, the butt joint between adjacent guards on the bed is located substantially in fore-and-aft alignment with the axis of rotation of a cutter so that it is remote from the weak point at the seams between adjacent modules and is in a position where any trash or other residue tending to get trapped can be easily severed by a knife of the cutter instead of being allowed to build up and cause harm.